Dynam Meteor - Page 173 - RC Groups
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Jan 14, 2013, 04:43 PM
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I ended up getting three Zippy compacts as that was all they really
had when i went to hit the button.
Capacity: 3700mAh
Voltage: 5S1P / 5 Cell / 18.5V
Discharge: 25C Constant / 35C Burst
Weight: 424g (including wire, plug & case)
Dimensions: 146x43x31mm
Balance Plug: JST-XH
Discharge Plug: HXT4mm

Hope they will do the job. Got to wait till the weekend to see if the weather will let me fly.
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Jan 14, 2013, 05:44 PM
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fg... a few retract things/tips....

First, on my Meteor - from the earlier days of doing retracts - I made "S bend pins". To get the oleo off the retract motor. This does work well.... but is messy to do! Hard to replicate an identical pair.... and you need to file flats on both accurately too.
Always use flats on pins/legs!! Softer metals you can use a file, but easier is a grinding wheel in a Dremel (eg 2mm wide one). Grind...test... adjust... grind...test.... bit by bit.

Second, it is useful to keep some pin exposed (which it must in that S bend case anyway), even if the pin is straight. This allows the pin to BEND if there is a stress situation above 'normal'... rather than tear out the retract. Of course only up to X amount above 'normal', after which damage is going to occur anyway! The aim is to try to make something cope with NORMAL stress levels, and bit of leeway (eg for harsh landings), so they last ongoing.... but have some easy to repair weak point if stress levels get worse.
One problem is that for the pin to be 'not too strong' it means it WILL bend over time from normal use - unless you land really well all the time, and not on grass/dirt. hehe
But there is no way around that..... trailing arm oleos, or just straight wire or spring coiled wire, help that a lot, followed by 'straight in' sprung oleos. And also spongier tires can too.

Another way to get an oleo to fit against a retract is to file a flat on that side. That depends on the oleo design and metal/alloy there that can be removed appropriately. (not filed down too far and make it too weak!)

You can also file a BIT off the retract, towards the trunion, where they are not 'flat' but curve upwards a bit. With exposed pin you wouldn't need to do that, but some cases of oleo right to the trunion you might need to do that.

For pins, you can use the often supplied soft metal ones... which will bend a lot, but that aborbs energy. Or if you can assess the total operation of trailing arms etc taking stresses, you might use piano wire - but it does not come in metric (eg not 3mm, 4mm etc) - seeing it will NOT bend much at all, but you assessed those other places will do that task well enough. Or use cut down motor shafts, which are 3mm, 4mm etc.... but then most of these are HARD (hardened) and thus need the rest of the leg/wheel to be the energy absorption points. Motor shafts will often shear off in a crash, as they are hardened and brittle - they should not break in normal use though - so that ability to shear off is useful, though needs quite a bit of force to reach that point.
Jan 14, 2013, 06:10 PM
TakeOff=optional,Landing= Must
fg1972's Avatar
Thanks Peter,
I always file a flat on shafts/pins where the grub screw meets the pin in all cases.
I have thought about filing a bit of a flat on the oleo itself so it can close a little further against the retract and this might be the go in this case.
The oleo in the picture accepts a 4mm pin and have used ~4mm piano wire. The Metal trinion 3mm hole has been drilled out to 3.5mm then 4mm to accept the ~4mm piano wire.
Last night I did a couple of hours making the wheel wells and too many hours just looking!
Jan 14, 2013, 06:50 PM
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autoquip, the main thing is to check any - and every - battery in operation. So fly them shorter first and see how they went. What recharge they needed... what sort of temp they came down at. So you can keep using them within their true capability bounds.

You can't go JUST by the recharge. eg 3700mAH, you recharged 2700mAH, looks good. But the TEMP after landing still over-rides what otherwise seemed fine in recharge terms.
If you used high power at the tail end of the discharge, it will be hotter than if you were cruising around then. The real enemy of batteries is HEAT, and the "80% discharge rule" is a rough guide only to more say "They get hotter as they discharge more, so keeping 20% in reserve means you were LESS into that higher heat area". It is not of real use to use as a hard and fast rule of what you can do every time.

Whether you use your hand, or a temp meter, it is hard to say specific temps to look for... but basically if you feel "that is pretty hot!" then you need to back off the use on that battery. One might act different to another of the exact same type (older, just different in manufacture etc), thus why each battery needs to be monitored.

I label all my batteries (eg like 5S 4000maH 30C - 01) and record their uses and recharges. Plus also label them (extra) if they have some issue or weakness etc. "70% effective", "Only use low power" etc. Based off how they have acted before. Like for eg one that runs pretty well from the start, but falls off in power after 2mins rather than 3mins, and if you push it longer it will get VERY hot so you know (by label) to use it for a short flight, and docile flight too. Or not in EDF anymore etc.
Though you really have to be careful with suspect batteries, as they can go downhill to be much worse at any time! Go too far and... HOT... and possibly burst and FIRE!

Keeping them down from running too hot means a longer life. Try to never Puff one. Just accept a shorter flight time.
Jan 14, 2013, 07:18 PM
TakeOff=optional,Landing= Must
fg1972's Avatar
Don't do what many new EDF pilots do at our club which is fly the jet like they stole it until they notice great loss of power to then decide its time to land and often don't make it back due to no power. When you check their batteries, they are hot like hell and have zero or very low % left in the battery.
Jan 14, 2013, 07:21 PM
Registered User
hehe yeah. Seen often enough!
I guess it depends on how much money you have to 'waste'! Not looking after batteries - which are expensive really.
Jan 14, 2013, 10:50 PM
Gravity impaired
jrjr's Avatar
My CS12 came today. Looks like a nice unit. Still waiting on my 2300 motor though.

I got my stock motor apart finally but was wondering, how do you guys hold the motor to get that retaining screw loose? I put it in a vice with tape on the jaws to protect it but it still dinged the metal up. I put one of the 3 protrusions on the back in the jaws.

The edf was worn almost all the way through from blade scrape when it came so I won't use that but the motor should still be good. After all its brand new. Will have to balance it for sure before use.

I know about filing the flats for the new one but the old one was really tight, as expected.
Jan 15, 2013, 12:33 AM
Registered User
Not a good idea to hold a motor by the alloy endcap vanes.
I held the fan blades (fingers with a strong hold/support of them) and used a steel ruler as the 'flat' on the fan holder.
But mine might have been a bit luckier case of not as madly tight as some people have had!
Jan 15, 2013, 06:58 AM
Gravity impaired
jrjr's Avatar
I think next time I will make some sort of a jig to hold it. This one was stupidly tight! I have a very large screwdriver that fit the groove good, and had to put vice grips on the screwdriver shaft for leverage to turn it. This is after putting in the freezer for a half hour.... oh well, its not dinged up that bad.
Jan 15, 2013, 07:37 AM
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On outrunners, those alloys 'arms' on the bell end are not overly strong. They are just alloy, and can be distorted quite easily. The slightest bend/twist (micro even!) means they spin off centre, or even touch magnets.
So whenever you do "things" to the motors, you have to think carefully about how to ensure any stresses are controlled right at the point you are working on. eg not held one end, work on the other, when they are high levels of force or stress. So as energy needs rise, to do something on it, know when to stop doing that and make sure you have it properly supported etc. - that might even not be possible and thus find another better way. (heating first?)

eg. Getting a motor shaft out - usually they are tight in the bell "hub".... support the bell right at the hub around the shaft and drive the shaft out. Either by drilling an exact hole size in wood to sit the bell's end hub into, or for the other direction by a tube over the shaft and inside the bell to the hub. Thus supporting the bell end right at the shaft perimeter in both cases.

I worked on about 5 motors before finding out how weak they really are! So that 6th one ended up with a warped bell... LOL. (its alloy arms got a twist in them - removing a motor shaft as per advised by someone, to do it in an incorrect manner! No proper support. "hold it over the end of a bench and tap it out with a hammer".... which COULD have worked ok too, if lucky, but is not a smart idea at all really.)
Jan 15, 2013, 01:42 PM
Registered User
I'm thinking to buy one of these setups for my Meteor to build it for speed:

I want to keep the weight down, so a small 6S lipo such as a 2650mAh is considered
has anyone tried it? I'm waiting for any opinions
Jan 16, 2013, 12:19 AM
Quest for Speed!!!
Mike_eee's Avatar
cant wait to get one..but gosh no one has them in stock in USA
Jan 16, 2013, 06:24 AM
Registered User
I finally made some effort and fit a Slide-Lock for the rear of the Meteor hatch.
The front had a 'tongue' fitted from the start, but the rear had magnets. After losing the hatch three times over a few months - and luckily all of them falling onto the football oval(!!) - it was about time I made a more solid and permanent solution! (as per almost all my other aircraft use).
I keep making it a rule to do it on all aircraft, but some have evaded it somehow!

Jan 17, 2013, 05:10 PM
Registered User
Thanks for all the advice. Just one more question. I launch underhand at full throttle with the 4s. Would you still advise full throttle on launch ,with the 5s?
Jan 17, 2013, 05:18 PM
Registered User
I don't hand launch my Meteor, but others I do full throttle, until/unless I work out it is OK or better to use X amount less. eg F-16's have amazing lift compared to what looking at them might suggest, and they fly away easily.
I am guessing that the Meteor probably does too really.... but it won't hurt to have leeway in power until you get to know it better.
4S I would say it would be a must-do! 5S will have that extra leeway - though I don't see any real reason to not use WOT on hand-launches all the time anyway.

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